JP2003514423A - Dual band transmission system and antenna therefor - Google Patents

Abstract

(57) [Summary] The antenna 1 of the two-band transmission system is a microstrip antenna. A short circuit S is provided at the rear edge 10 of the main body 31 of the patch 6 of the microstrip antenna, so that a quarter-wave type primary resonance can be excited from the connecting wire C1. A slot 17 extends into the patch from the periphery of the patch, separating the body and the tail 33. The tail maintains a connection to the body by way of a passage 32. The secondary resonance mode utilizes the body, the passage and the tail. The secondary resonance mode can be excited from the same connection wire at twice the primary resonance frequency. The short circuit is obtained by components attached to the edge of the antenna substrate and can have an inductive component, a resistive component and a control component. The invention applies in particular to the implementation of a two-mode mobile radio system using the GSM and DCS standards.

Description

Detailed Description of the Invention

The present invention relates generally to wireless transmission systems, and in particular to mobile phones, and more particularly
It relates to a microstrip antenna included in such a system.

Antennas of this type usually include a patch formed by etching a metal layer. Those skilled in the art refer to this type of antenna as a "microstrip patch antenna".

Microstrip technology is a planar technology used to fabricate signal transmission lines and antennas that provide coupling between signal transmission lines and radiated waves. Planar technology uses conductive patches and / or strips formed on the top surface of a thin dielectric substrate. The conductive layer extends on the bottom surface of the dielectric substrate and constitutes the ground plane of the transmission line or antenna. Usually, patches of the above type are wider than strips of the above type, and their shape and dimensions determine important characteristics of the antenna. The dielectric substrate is usually a rectangular flat sheet of constant thickness, likewise the patch is rectangular, but this is not necessary. In particular, the person skilled in the art knows that by varying the thickness of the substrate, the bandwidth of the above-mentioned type of antenna can be widened and the patch can be of various shapes, for example circular. The electric field lines extend through the substrate between the strip or patch and the ground plane.

The above techniques differ from various other techniques that also use conductive members on thin substrates, and in particular, coplanar line techniques. In coplanar line technology, an electric field is established on the upper surface of the substrate and between a central conductive strip and two conductive regions separated from the strip by two slots and on opposite sides of the strip. The electric field is established symmetrically. In the case of a loop slot antenna, a continuous conductive area surrounds the patch, and the patch is separated from the conductive area by the slot.

Usually, an antenna constructed using the above technique, although not necessarily, constitutes a resonant structure, whereby a standing wave causes a coupling with a radio wave radiated in the air. .

Various types of resonant structures can be implemented using microstrip technology, and various resonant modes can be used. Hereinafter, the resonance mode will be simply referred to as “resonance”. Broadly defined, each such resonance can be described as a standing wave formed by superposition of two traveling waves propagating in the opposite direction in a common path. The two traveling waves are generated by the same traveling electromagnetic wave being reflected alternately at each of the two ends of the path. In the context of this kind of description, an electromagnetic wave is considered to propagate in an electromagnetic line consisting of a ground plane, a substrate, and a patch, and that electromagnetic line defines a zero-width linear path. I shall. In practice, electromagnetic waves of the above kind have a wavefront that extends across the entire section provided by the antenna, which means that the above description sometimes greatly simplifies real-world situations. is doing. The path may be straight or curved as long as it can be considered linear. Less than,
The path is called a "resonance path". The resonance frequency is inversely proportional to the time required for the traveling wave described above to travel along its path.

The first type of resonance is a type of resonance that can be referred to as a “half-wavelength” resonance, where the length of the resonant path is typically substantially one-half the wavelength, ie Equal to half the wavelength of the wave. In this case, the antenna is called a "half wave" antenna. Normal,
This kind of resonance can be defined by the presence of a current node at each of the two ends of a path of the above kind, so that the length of the path is
The length can be obtained by multiplying an integer other than 1. Usually this integer is an odd number. Coupling with the radiated wave occurs at at least one of the two ends of the path,
Both ends of the path exist in the region where the electric field amplitude is maximum in the substrate.

A second type of resonance obtained using the same technique can be referred to as a "quarter wavelength" resonance. This resonance differs from the half-wave resonance firstly in that the length of the resonance path is usually substantially equal to ¼ of the wavelength, ie ¼ of the wavelength defined above. Therefore, the resonant structure must have a short circuit at one end of the path. The expression "short circuit" means the connection between the ground plane and the patch. The impedance of the short circuit must be small enough to force resonance. Usually, this kind of resonance can be defined by the presence of an electric field node which is fixed by a short circuit of the above type provided near the edge of the patch and by a current node at the other end of the resonance path. Therefore, the length of the resonance path is added to the quarter wavelength,
It can be equal to an integral multiple of half wavelength. The coupling with the radio waves radiated in the air,
It occurs at the edge of the patch in the region where the amplitude of the electric field passing through the substrate is large enough.

Other types of somewhat complex resonances can be established in antennas of the above type. Each resonance of this type has a spatial domain that includes the antenna and its immediate vicinity,
Characterized by the distribution of the oscillating electric and magnetic fields. This type of resonance depends in particular on the configuration of the patch, in particular on the configuration of the patch, which can incorporate slots, possibly radiation slots. It is also possible to treat the presence and location of a short circuit, and the equivalent of a perfect short circuit with zero impedance, even if the short circuit is incomplete, i.e. almost perfect. It depends on the electrical model that represents these short-circuits when they cannot.

The presence of imperfect short circuits in the antenna can result in resonant features that can be referred to as virtual nodes. A virtual node occurs when some of the following conditions are met at the same time. The condition when the above antenna is referred to as a “first antenna” is that the distribution of the electromagnetic field in the first antenna can be induced in the same area of the patch of the second antenna, and Is the same as

The second antenna is identical to the first antenna in the area. However, the case where the second antenna does not have the short circuit in the above area is excluded.

The patch of the second antenna extends not only on the above-mentioned area forming the main area of the second antenna, but also on the complementary area.

The distribution of the electromagnetic field in the main area of the second antenna is accompanied by the electric field node or magnetic field node in the complementary area.

When describing the resonance that occurs in the first antenna, it can be considered that the node that occurs in the second antenna also constitutes the node for the first antenna to resonate. Since this node is in an area outside the patch of antennas, and therefore there is no electric or magnetic field in that area that can directly determine the presence of the node, for antennas like the first antenna, This type of node is called a "virtual" node.

Although these “virtual nodes” have not traditionally been considered in the term “virtual node” when describing resonances, “virtual nodes” are the physical or geometrical parts of the same patch. Implicitly included in the sometimes drawn distinction between long and so-called electrical lengths. For the two antennas referenced above, and for the patch of the first antenna, the physical or geometric length is the length of the patch, and the electrical length of that same patch is actually , The physical or geometrical length of the second antenna.

Multiple resonances can be generated for a particular antenna configuration. The multiple resonances allow the antenna to be used at each of the resonant frequencies.

The antenna typically comprises a connection line external to the antenna, such as a transmitter, via a connection system terminating in a coupling system integrated in the antenna for coupling the line to the resonant structure of the antenna. Is coupled to the signal processor. The resonance of the antenna also depends on the nature and position of the connection system. In the case of a transmission antenna, the connection system is sometimes called the feeder of the antenna.

The present invention relates to various types of systems such as mobile telephones, transceiver base stations for mobile telephones, automobiles and aircraft, or onboard missiles. For mobile phones, the continuity of the bottom ground plane layer of the microstrip antenna can easily limit the radiation disturbed by the body of the user of the system.
In the case of motor vehicles and, in particular, in the case of aircraft or missiles whose outer surface is a metal surface and has a curved contour with a very low aerodynamic resistance, adapt the antenna to that contour so as not to create unwanted additional aerodynamic drag Can be

The invention relates more particularly to the situation in which a microstrip antenna must have the qualities listed below.

A dual frequency antenna, ie an antenna which must be able to efficiently transmit and / or receive radiated waves of two frequencies separated by wide spectral spacing.

For all operating frequencies of the transmission system, it is possible to connect to the signal processor by means of a single connection line, without causing undesired and troublesome standing wave ratios in the line.

To achieve the above attributes, the use of frequency multiplexers or demultiplexers should not be required.

Many microstrip antennas having the above three characteristics have been manufactured or proposed in the art. They differ from each other in the means they use to obtain multiple resonant frequencies. The three types of microstrip antennas are considered below.

A first prior art microstrip antenna is disclosed in US Pat. No. 4,766.
, 400 (Gegan). The shape of the patch 10 of the antenna is generally rectangular, allowing the antenna to have two half-wavelength resonances in which a resonant path is established along the length of the patch and across the width of the patch. The antenna also has a U-shaped curved slot that is entirely inside the patch. The slot is a radiating slot, creating an additional resonant mode in another path. The slot is further tuned by appropriately selecting its shape and dimensions to tune the frequency of the resonant mode to the required value, thereby causing a circular polarization by associating two modes with the same frequency and cross linear polarization. Wave brings the function of transmitting radio waves. The coupling system takes the form of a microstrip line, which can also be said to be coplanar with the microstrip in the patch plane and between two notches in that plane. . The coupling system includes impedance matching means for matching the system to various input impedances of the line at various resonant frequencies used as operating frequencies.

[0025]   The first antenna according to the prior art has the following drawbacks.

[0026]   It is necessary to provide impedance matching means, which complicates the antenna.

[0027]   It is difficult to precisely adjust the resonance frequency to the required value.

The second antenna according to the prior art differs from the first antenna in that it uses only one resonance path. The second antenna is described in US Pat. No. 4,771,291 (LO et al.). The antenna patch includes a localized short circuit and a slot extending along a straight line segment within the patch. The slot and the short circuit share the path and between two frequencies corresponding to two resonances with two different modes, represented by the numbers (0,1) and (0,3). The difference is small. That is, the common path is occupied by one half wavelength or three half wavelengths, depending on the mode. Therefore, the ratio of the above two frequencies can be reduced from 3 to 1.8. The localized short circuit is formed of a conductor penetrating the substrate.

This second prior art antenna has the drawback that its manufacture is complicated by the inclusion of a localized short circuit, in particular.

The third prior art dual frequency antenna differs from the above two types of antennas in that it uses quarter wavelength resonance. For dual frequency antennas, see IEEE ANTENNAS AND PROPAGATION SOCIETY INTERNATIONAL SYMPOSIUM DIGEST
, NEWPORT BEACH (June 18-23, 1995, pages 2,124-2,027) by Boag et al. "Dual Band Cavity-Backed Qu"
"Arter-wave Patch Antenna". The first resonant frequency is defined by the dimensions and characteristics of the antenna substrate and patch. By using the matching system, substantially the same type of resonance is obtained on the same resonance path at the second frequency.

[0031]   This third prior art antenna has the following drawbacks.

[0032]   The difference between the two resonant frequencies is too small for some applications.

[0033]   A matching system must be used, complicating the antenna.

It is necessary to use the antenna coupling system in the form of a coaxial line, which complicates the antenna.

[0035]   The present invention has the following objects in particular.

[0036]   Simplify the implementation of dual frequency antennas.

It allows a more conventional choice of the ratio of the center frequencies of the two operating bands of the transmission system, and more particularly the ratio of the two required resonant frequencies of the antenna is between about 1.25 and about 5. Providing an antenna for the transmission system so that it is close to 2, in particular.

Giving the antenna a bandwidth centered on each of the two resonant frequencies. The bandwidth is of sufficient width to allow the transmit and receive frequencies of the system to be placed in each of the two bands without crosstalk.

[0039]   To allow easy and accurate adjustment of the two resonant frequencies.

Allowing the use of a single coupling system where the impedance can be easily matched to each of the two resonant frequencies.

[0041]   Limit the dimensions of the antenna.

With the above objects in mind, the present invention is particularly directed to transmitting and / or receiving electrical signals in each of two operating bands centered at their respective predetermined center frequencies. A dual band, comprising a signal processor configured to tune in band, a microstrip antenna, and an antenna connection system including an electrical conductor connecting the signal processor to the antenna for coupling the electrical signal to a radiated wave. In the transmission system, the antenna has a conductive ground plane, a conductive patch having a peripheral portion, a short circuit formed in the peripheral portion, and a starting point including an opening in the peripheral portion, A separation slot entering the patch from a starting point, the short circuit and the separation slot creating two resonances in the antenna. And one of the two resonances is a quarter wavelength type resonance having at least one virtual electric field node fixed by the short circuit, substantially the two center frequencies. A primary resonance having a primary frequency equal to one of the two resonances, the other of the two resonances forming a secondary resonance having a secondary frequency substantially equal to the other of the two center frequencies, An electrical conductor includes the ground plane and a main antenna coupling conductor that is part of the patch, whereby the antenna can be coupled to the signal processor near each of the two center frequencies, The transmission system is configured such that the separation slot extends into the patch until the rear end of the separation slot is located a sufficiently small distance from the perimeter. A body including a tena coupling conductor and the short circuit, a tail without the short circuit that is electrically connected to the connection system only by the body, and an area of the patch between the rear end and the periphery. And a separation slot partially partitioning the patch into a dual band transmission system.

The distance of the separation slot from the patch periphery is from the rear end of the slot over the entire length of the slot except for the vicinity of the origin of the slot, or over at least most of its length, and on both sides. It is preferably longer than the distance to the peripheral portion.

The origins of the separation slots are preferably in the vicinity of the short circuit in order to give the two resonances to the respective resonance paths extending from the short circuit. Preferably, one of the two paths extends only into the body and the other path extends into the body and into the tail.

Various aspects of the present invention will be better understood from the following description and the accompanying schematic drawings. When two components are represented by the same reference signs and / or letters in the figures, they have the same function or are the same components in the two embodiments of the invention. Is.

As shown in FIGS. 1-3 and as is known in the art, the resonant structure of the antenna according to the present invention includes the following components.

A dielectric substrate 2 having two mutually opposite major surfaces extending in horizontal directions DL and DT defined with respect to the antenna and which can be determined by the area of the antenna. The substrate can take various forms, as already explained. The two main surfaces form a bottom surface S1 and a top surface S2, respectively.

For example, a bottom conductive layer that extends over the entire bottom surface and constitutes the ground plane 4 of the antenna.

An upper conductive layer that extends above the ground plane 4 and extends over a region of the upper surface to form the patch 6. In general, the patches extend in two horizontal directions with a constant length and a constant width, and form a vertical direction DL and a horizontal direction DT. The perimeter can be considered to consist of four edges extending in pairs in substantially the two directions. Generally, the terms "length" and "width" apply to two dimensions of a rectangular object at right angles to one another, referring to length being greater than width, but patch 6 departs from the scope of the invention. It has to be understood that the rectangular shape can be deviated significantly without having to. Usually one of these edges extends in the lateral direction DT and constitutes the rear edge which comprises two segments 10 and 11. The front edge 12 is opposite the rear edge. The two side edges 14 and 16
The rear edge is joined to the front edge.

A short circuit that electrically connects patch 6 from segment 10 at the rear edge of the patch to ground plane 4. In the first and second embodiments of the present invention, the short circuit is formed by the conductive layer S extending on the edge surface of the substrate 2. The edge surface is usually flat and constitutes the short circuit plane. In the third embodiment, the short circuit is composed of three discrete components R, L and D connected in parallel between the ground plane 4 and the patch 6. In each embodiment, the short circuit forces at least one resonance of the antenna to have at least one virtual field node in the vicinity of the segment 10 and to become a quarter wavelength type resonance. There is. This resonance and its frequency are hereinafter referred to as "primary resonance" and "primary frequency". The back edge, the front edge and the side edges, and the longitudinal and lateral directions, are short circuit large enough to force resonance in an antenna having such a field node, i.e. As long as the impedance is small enough, it is defined by the location of this kind of short circuit.

The antenna further comprises a coupling system, which comprises a main conductor consisting of a coupling strip C1 on the upper surface S2 of the substrate. This strip is
It is connected to the patch 6 at a connection point 18. The connection point 18 is, for example,
It can be provided on the front edge 14. The distance from the rear edge 10 to this joining point constitutes the connecting dimension. The coupling system further includes a conductive ground plane consisting of layer 4. The conductive ground plane is part of a connection system that connects the resonant structure of the antenna to the signal processor T, for example, if the antenna is a transmitting antenna, the processor excites one or more resonances of the antenna. It In addition to the above systems, the connection system usually includes a connection line outside the antenna. The connecting lines can be coaxial, microstrip or in particular coplanar type lines. In FIG. 1, the connection line is
Although shown by the symbol of the two conductors C2 and C3 connecting the ground plane 4 and the strip C1 to the two terminals of the signal processor T respectively, in practice this connecting line is a microstrip or coaxial. It should be understood that it is preferable to take the form of a line.

The signal processor T is configured to operate at a predetermined operating frequency that is at least close to the required antenna resonance frequencies, ie, in a band centered around these resonance frequencies. The signal processor can be a complex system and can have components permanently tuned to each operating frequency. Alternatively, it can have components that can be tuned to different operating frequencies. The primary resonance frequency constitutes one of such necessary resonance frequencies.

In accordance with the present invention, the separation slot 17 includes the back edges 10 and 11 of the patch to the back edge 15 of the slot, the side edges 14 and 16, and the front edge 12.
Extend away from. Therefore, the body 31 is connected to the tail 3 by the tail connecting passage 32.
Connected to 3. The passage has a length W2 in the DT direction and a width L2 in the DL direction between the front edge 14 and the rear end 15. The main body has a width W1 in the DT direction. The slot 17 has a rear edge that is part of the body 31
Moreover, the main body base 10 including the short circuit S and the tail portion base 11 which is a part of the tail portion 33 and has a width W4 in the lateral direction DT are divided. The tip 13 of the tail is
It consists of a region that joins the tail onto the passage 32. The length of the tail extends from the base 11 to the chip in the direction of DL. The width of the tail is defined at each point in the length of the tail and extends in the direction of DT.

In the context of the first embodiment of the invention shown in FIG. 1, the width of the body, passage and tail of the patch is uniform and an antenna with such a uniformly formed patch is In general, the requirements of mobile telephone technology can be met, where the ratio of primary frequency to secondary frequency can be close to 2: 1.

However, it seems that the second embodiment is preferable to the first embodiment. Second
In the embodiment described above, the width W4 of the base 11 of the tail portion 33 is wider than the width W2 of the tip 13. The tail width preferably extends from the tip to the base while going through a plurality of intermediate values between the width of the tip and the width of the base. It is further preferred that this increase in tail width is continuous, the shape of the tail being, for example, a trapezoid, each of its large and small bases being the base of the tail and a tip.

It is further preferable that the length L3 of the tail portion 33 is 50% to 100% of the length L1 of the main body 31, and the ratio F2 / F1 of the secondary frequency F2 to the primary frequency F1.
Is preferably 1.9 to 2.1.

It is further preferred that the width W4 of the base 11 of the tail 33 is between 50% and 150% of the width W1 of the main body 31, but the passage 32 and the tip 13 of the tail constitute a connecting system for the tail. And the narrower width combination constitutes an effective tail connection width, the effective width W3 is 10% of the width W4 of the base.
It is preferably 70%.

In the second and third embodiments of the present invention, the substrate 2 has a bottom dielectric layer 21 supporting the ground plane 4 and an upper dielectric layer 22 supporting the patch 6 in at least part of its area. It is preferable to include two different superposed layers respectively constituting the above. Advantageously, the top dielectric layer has a higher dielectric constant and a lower thickness than the bottom dielectric layer, and the two layers advantageously extend over the entire area of the substrate. Due to the difference between the two layers, the long-range radiation efficiency is improved and the resonance frequency is easily adjusted.

The antenna preferably further comprises, in a part of the area of the patch 6, a conductive insert 23 extending between the top dielectric layer 21 and the bottom dielectric layer 22. This part advantageously extends below the passage 32 and in the vicinity of the front edge 12. The insert has a width L = 5 mm and a length W5 = 20 mm, the length of which is an intermediate length which corresponds to the intermediate value of the front edge 12. The insert has the advantage that the secondary frequency can be adjusted by selecting its position and dimensions without modifying the primary frequency in a tedious way.

In a variant, which is not shown, the same advantages are obtained by using a tongue made of copper film, which is continuous with the body 31 and projects from the body and the substrate at the front edge 12 part. Obtainable. A tongue of this kind is free to bend on the front edge 12 away from the patch plane and towards the vertical plane of the substrate. Therefore, the necessary frequency adjustment is carried out by selecting its slope.

In the context of the first and second embodiments, various compositions and values are given below by way of example. The length and width of the substrate are shown with respect to the vertical direction DL and the horizontal direction DT, respectively. The antenna ground plane covers the bottom surface of the substrate, and the short circuit S occupies the entire width of the base of the main body 31.

[0062]   The values given below are valid for each of the above two embodiments.

[0063]   Primary resonance frequency: F1 = 980 MHz   Secondary resonance frequency: F2 = 1,900 MHz   Input impedance: 50Ω   Conductive layer composition: copper   Conductive layer thickness: 17 μm   Width of conductor: C1 = 5 mm.

[0064]   The values shown below are valid for the first embodiment.

Substrate length: 30 mm Substrate width: 20 mm Substrate composition: PTFE with relative permittivity εr of 5 and dielectric loss tangent tan δ of 0.002
Fluorine resin-based laminate, etc. Substrate thickness: 5 mm Patch length: 20 mm Patch body width: 13 mm Connection dimension: 2 mm Separation slot width: 3 mm Separation slot length: 25 mm Tail width: 4 mm Bandwidth centered around the primary and secondary frequencies: 2.
5% and 2%, provided that the standing wave ratio is 3.5 or less.

[0066]   The values shown below are valid for the second embodiment of the present invention.

Substrate length: 32 mm Substrate width: 26 mm Substrate bottom layer 21 composition: low dielectric constant foam Substrate bottom layer thickness: 2 mm Substrate top layer 22 composition: relative permittivity εr is 5, dielectric loss tangent tan δ is 0.002
Fluorine resin-based laminate such as PTFE of the above. Thickness of upper layer of substrate: 3mm Patch length: L1 = 32mm Body width of patch: W1 = 12mm Connection dimension: L4 = 2mm Passage length: W2 = 4mm Width of passage: L2 = 2 mm Tail 33: Symmetrical about axis parallel to front edge 14 Width of tip 13 of tail 33: W3 = 2 mm Width of base 11 of tail 33: W4 = 12 mm Length of tail 33: L3 = 30 mm Bandwidth centered on the primary and secondary frequencies: 3.
5% and 4%, provided that the standing wave ratio is 3.5 or less.

[0068]   The operation of these two embodiments of the antenna will now be described.

On the one hand, the coupling between the standing waves of the primary resonance and the secondary resonance, and on the other hand, the coupling between the radio waves radiated into the air occurs mainly at one end of the patch 6.
This edge is called the primary radiating edge or the secondary radiating edge, depending on the resonance.

In the first embodiment of the present invention, the front edge 12 is the primary radiating edge and corresponds to a quarter-wave type primary resonance having an electric field node on the segment 10. However, it can be seen that the presence of the passage 32 and the tail 33 causes the primary frequency to have a value that suggests that the path of its resonance is slightly extended. If the length of the patch is forced, the extension of the resonance path as described above allows the value of the primary frequency when the slot 17 is present to be smaller than the value when the slot 17 is not present. Should be. In the typical situation where the value of the primary frequency is enforced, the presence of the slots is advantageous, and is generally a configuration goal, as it allows the length of the patch to be reduced. This advantage will be maintained even if the antenna is included in a single band transmission system that uses only the primary resonance of the antenna.

In the first embodiment, the secondary radiating edge consists of the base 11 of the tail 33. It is suggested that the path of the secondary resonance extends not only from the short circuit S to the length of the main body 31 but also from the length of the passage 32 and the tail portion 33, and the length of the path is one by the short circuit S. Forced, the other is closer to the tip 13 of the tail 33,
It can be seen that the secondary frequency has a value that suggests that the resonance is essentially a half-wavelength type resonance, even though it is close to three quarter wavelength with two field nodes. .

In a second embodiment of the invention, the base 11 of the tail 33 is the primary radiating edge and extends from the short circuit S to the length of the body 31 as well as the quadrant spanning the length of the passage 32 and the tail 33. It can be seen that the primary frequency has a value suggesting that it is a one-wavelength type primary resonance path. Therefore, in a typical situation where the value of the primary frequency is forced, the presence of the slot 17 allows the patch length to be further shortened as compared with the case of the first embodiment.

In the second embodiment, the front edge 12 is a secondary radiation edge. The secondary frequency has a value that suggests that the secondary resonance path extends the length of the body 3 and that the resonance is substantially a quarter wavelength type resonance. I understand that.

As shown in FIG. 2, in the case of the second embodiment, the main body 31 has a protrusion 34 in the plane of the patch 6 and protrudes from the front edge 14 near the front edge 12. It is preferable. In the context of the present invention, it has been found that such a protrusion has the advantage of widening the resonance bandwidth of the antenna. This protrusion can be rectangular in shape, in which case the length L6 = 10 mm and the width W6 = 6 mm. A protrusion 34 of this kind in the fourth embodiment of the invention is shown in FIG. In FIG. 5, the protrusion projects from the rear edge 10 near the front edge 14.

In the configuration used in the third embodiment of the invention, shown in FIG. 4, which is the preferred embodiment for some applications, the impedance of the short circuit at the primary frequency is relatively high, Therefore, its primary resonance is substantially different from the resonance that could be induced in the antenna near its frequency if the impedance of the short circuit were zero. At the same time, in order to fix at least one virtual electric field node of resonance near the base 10 of the main body 31, the impedance of the short circuit at this primary frequency is relatively small. It therefore has the disadvantage of complicating the short circuit, but in some cases also has enormous advantages, and by properly selecting the components of the impedance of the short circuit according to the invention, the resonance or antenna To match the physical properties of the antenna and allow better use of the antenna than if the impedance of the short circuit is zero.

More specifically, the impedance of the short circuit preferably has an inductive component L. This kind of inductive component causes a quarter wavelength type resonance with virtual electric field nodes at the rear of the base 10, ie outside the patch 6. This includes
When the primary resonance frequency F1 is forced, there is an advantage that the length of the patch can be further shortened.

The impedance of the short circuit can also have a resistance component R, which brings the advantage of widening the bandwidth of the antenna. It is also possible for the impedance of the short circuit to have a control component in the form of a diode D shunted by a decoupling capacitor (not shown). This type of component has the advantage of allowing control of the resonant frequency or bandwidth of the antenna. Each of the above configurations can be easily realized by using at least one discrete component connected between the patch 6 and the ground plane 4.

Each of the above advantages referred to with respect to the selection of the impedance component of the short circuit that forces a quarter-wave type resonance, has the advantage that if only a quarter-wave resonance is used and / or the patch is It could also be obtained with an antenna that does not include the slot 17 described above.

In the second and third embodiments of the present invention, the substrate 2 comprises a bottom dielectric layer 21 supporting the ground plane 4 and an upper dielectric layer supporting the patch 6, at least in part of its area. It is preferred to include two different superposed layers, each constituting 22. It is advantageous for the top dielectric layer to have a higher relative permittivity and possibly a lower thickness than the bottom dielectric layer, and for the two layers to extend over the entire area of the substrate. . Due to the difference between the two layers, the long-range radiation efficiency is improved and the resonance frequency is easily adjusted.

It is further preferred that the antenna comprises a conductive insert 23 in a part of the area of the patch 6 between the bottom dielectric layer 21 and the top dielectric layer 22. This part advantageously extends below the passage 32 and in the vicinity of the front edge 12. The insert has a width L = 5 mm and a length W5 = 20 mm, the length of which is an intermediate length which corresponds to the intermediate value of the front edge 12. The insert has the advantage that the secondary frequency can be adjusted by selecting its position and dimensions without modifying the primary frequency in a tedious way.

In one embodiment not shown, a similar advantage is obtained by a tongue made of a thin copper film which is continuous with the body 31 and which projects from the body and the substrate at the front edge 12 part. You can A tongue of this kind can be freely bent at the front edge part, either pulling the tongue away from the patch plane or directing it to the vertical plane of the substrate edge. Therefore, the required frequency adjustment is obtained by selecting its slope.

As shown in FIG. 5, the fourth embodiment of the antenna according to the invention is particularly characterized in that the origin O of the separation slot 17 and the short circuit S are located near the common point of the rear side 10 and the tail side 16. This is different from the above antennas. The edges of the isolation slots are concave on the same side as the body 31 and convex on the same side as the tail 33, in order to impart two resonances to the two resonance paths extending from the short circuit. One of the two paths extends only into the body, the other path extends into the body and into the tail. Furthermore, the antenna coupling strip C1 and the protrusion 34 are coupled at the rear edge 10. This antenna has the particular advantage of high bandwidth.

In the context of the fourth embodiment above, various compositions and values are given below by way of example. As shown in FIG. 6, the length and width are shown for the longitudinal direction DL and the lateral direction DT, respectively. The abscissa “x” and the ordinate “y” are measured in the same direction as the vertical direction and the horizontal direction from the starting point of the separation slot in the peripheral portion of the patch. The ground plane of the antenna covers the bottom surface of the substrate.

Primary resonance frequency: F1 = 910 MHz Secondary resonance frequency: F2 = 1,800 MHz Bandwidth centered on the primary frequency and the secondary frequency: 9% of the respective frequency
And 8%, but measured at a standing wave ratio of 3 or less Input impedance: 50Ω Conductive layer composition: copper Conductive layer thickness: 200 μm Substrate composition: relative permittivity εr is 1, dielectric loss tangent tan δ is 0 .0001 foam Substrate thickness: 7mm Patch 6 length: W1 = 24mm Patch body width: L1 = 35mm Strip C1 width: 1.5mm Short circuit S width: L4 = 3.5mm Connection dimension: L5 = 5 mm Separation slot 17 width: 1.5 mm Separation slot 17 length: 50 mm Maximum abscissa "xm" reaching the slot path: 21 mm Slot end ordinate "xe": 8 mm Slot end ordinate "ye" : 32 mm Maximum width of the protrusion 34: L6 = 5 mm Maximum length of the protrusion: W6 = 10 mm.

By adjusting the size of the protrusion, the spectral position of the antenna band can be finely adjusted.

In this fourth embodiment, the front edge 12 and the tail edge 16 each constitute a primary radiating edge, and the quarter-wavelength type primary resonant path from the short circuit S leads to the passage 32. It can be seen that the primary frequency has a value that suggests that it extends over the length of the tail 33 as well as the body 31. In this embodiment, the leading edge 14, the trailing edge of the slot 17, and the trailing edge 10 of the patch each constitute a secondary radiating edge, suggesting that a secondary resonant path is contained within the body 31. , And that the secondary frequency has a value that suggests that the resonance is a relatively complex type of resonance.

[0087]   The present invention also provides the antenna described above.

The antenna is particularly applicable to mobile telephone systems. The mobile telephone system includes a transmitting / receiving base station and a mobile terminal, and can be implemented under the GSM standard using a frequency close to 900 MHz and / or the DCS standard using a frequency close to 1800 MHz. In this type of system, each base transceiver station or mobile terminal may comprise a transmission system according to the invention. In this type of system suitable for use with the transmission system according to the invention, the antenna can be operated in a high frequency band near the secondary frequency and in a low frequency band near the primary frequency. Therefore, the processor T can be tuned to four different operating frequencies shown below.

[0089]   High transmission frequency in high frequency band   High reception frequency in high frequency band   Low transmission frequency in low frequency band   Low reception frequency in the low frequency band.

The processor is configured to transmit or receive a signal, respectively, when tuned to one of the transmit frequencies or one of the receive frequencies.

The present invention not only prevents crosstalk between transmit and receive channels within a band, but also allows the location of the channel within the band to be selected from multiple options. Each is wide enough.
The low frequency band corresponds to the GSM standard and the high frequency band corresponds to the DCS standard. This is an economical way of implementing a base transceiver station and / or a bi-mode terminal, ie a terminal configured to operate in the context of any of the above standards.

For example, the high transmission frequency and the high reception frequency may be 1,750 MHz and 1,840 MHz, respectively, and the low transmission frequency and the low reception frequency may be 890 MHz and 940 MHz, respectively.

[Brief description of drawings]

[Figure 1]   FIG. 3 shows a patch of a first embodiment of an antenna according to the present invention.

[Fig. 2]   FIG. 6 shows a patch of a second embodiment of an antenna according to the present invention.

[Figure 3]   3 is a perspective view of a transmission system including an antenna having the patch shown in FIG. 2. FIG.

[Figure 4]   FIG. 7 is a partial view of the rear of a third embodiment of an antenna according to the present invention.

[Figure 5]   FIG. 6 shows a patch of a preferred fourth embodiment of an antenna according to the invention.

[Figure 6]   FIG. 6 is a diagram showing separation slots of the patch shown in FIG. 5.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01Q 9/40 H01Q 9/40 H04M 1/02 H04M 1/02 C F term (reference) 5J045 AA01 AA03 AA05 AB05 DA08 EA07 HA06 MA04 NA01 5J046 AA02 AA04 AA07 AA12 AB13 PA07 5J047 AA02 AA04 AA07 AA12 AB13 FD01 5K023 AA07 BB06 LL05

Claims (24)

[Claims] 1. A signal processor configured to tune in two operating bands for transmitting and / or receiving an electrical signal in each of the two operating bands centered on a respective predetermined center frequency. (T), a microstrip antenna (1), and an antenna connection system including electric conductors (C1, C2, C3, C4) for connecting the processor to the antenna for coupling the electric signal into a radiated wave. including,
A dual band transmission system, wherein the antenna comprises: a conductive ground plane (4), a conductive patch (6) having a peripheral portion (10, 12, 14, 16), and a short circuit formed in the peripheral portion. A circuit (S), and a separation slot (17) having a starting point (O) formed of the opening of the peripheral portion and entering the patch from the starting point; It is possible to establish two resonances, one of said two resonances being a quarter wavelength type resonance having at least one virtual electric field node fixed by said short circuit, substantially said A primary resonance having a primary frequency (F1) equal to one of the two center frequencies, the other of the two resonances being substantially equal to the other of the two center frequencies (F2). Forming a secondary resonance with the electrical conductor of the connection system including the ground plane and a main antenna coupling conductor (C1) that is part of the patch, the antenna being coupled to each of the two center frequencies. Can be coupled to the signal processor (T) in the vicinity of the slot, until the rear end (15) of the separation slot (17) is located at a sufficiently small distance from the periphery that the transmission system A body (31) extending into the patch and including the main antenna coupling conductor and the short circuit; a tail (33) without the short circuit and electrically connected to the connection system only by the body;
A dual band transmission system, characterized in that the separation slot partially divides the patch into a passageway (32) consisting of a region of the patch between the rear end and the periphery. 2. The distance from the periphery of the separation slot (17) extends over most of the length of the separation slot and on both sides of the rear end (15).
The transmission system according to claim 1, wherein the transmission system is longer than the distance from the peripheral part to the peripheral part. 3. The distance of the separation slot (17) from the periphery is from the rear end (15) over the entire length of the separation slot except on the vicinity of the origin (O) and on both sides. The transmission system according to claim 1, wherein the transmission system is longer than a distance to the peripheral portion. 4. The origin (O) of the separation slot (17) is close to the short circuit (S) in order to give the two resonances to the respective resonance paths extending from the short circuit (S). Yes, one of the two paths extends only into the body (31) and the other of the two paths extends into the body and into the tail (33). The transmission system according to Item 1. 5. A dielectric having two main surfaces opposite to each other, the antenna extending in a horizontal direction (DL, DT) of the antenna and constituting a bottom surface (S1) and a top surface (S2), respectively. Body board (
2), a bottom conductive layer extending over the bottom surface and constituting the ground plane (4) of the antenna, and over the area of the top surface above the ground plane, the patch (6)
), And the patch (6) from the peripheral segment of the patch to the ground plane (
4) with the short circuit (S) electrically connected to the antenna coupling system (C1, 4) forming part of the antenna connection system.
) And the transmission system according to claim 1. 6. The antenna coupling system (C1, 4) is a microstrip line including a strip constituting the main antenna coupling conductor (C1) and the ground plane (4). The transmission system according to claim 5. 7. The patch (6) is generally rectangular in shape, the peripheral portion comprising the short circuit (S), a rear edge constituting a rear edge (10, 11), and the rear edge. Opposite opposite front edges forming a front edge (12) and two sides joining the rear edge to the front edge to form a front edge (14) and a tail edge (16) respectively. An edge, wherein the length (L4) of the patch extends in the vertical direction (DL) between the rear edge and the front edge (12) in the horizontal direction. 1
Transmission system according to claim 5, characterized in that the width of the patch extends in the horizontal direction between two side edges of the patch and forms a lateral direction (DT). . 8. The impedance of the short circuit (R, L, D) at the primary frequency is relatively large and the primary resonance causes the antenna to be near the frequency when the short circuit has no impedance. 3. The impedance at said frequency is relatively small, substantially different from the inducible resonance and at the same time fixing at least the virtual electric field node of said resonance in the vicinity of said short circuit. 5. The transmission system according to item 5. 9. System according to claim 8, characterized in that the impedance of the short circuit (R, L, D) has an inductive component (L). 10. System according to claim 8, characterized in that the impedance of the short circuit has a resistance component (R). 11. System according to claim 8, characterized in that the impedance of the short circuit has a control component (D). 12. The short circuit (R, L, D) comprises at least one discrete component connected between the patch (6) of the antenna and the ground plane (4). 9. The system of claim 8 characterized. 13. The dielectric substrate (2) comprises a bottom dielectric layer (21) supporting the ground plane (4) and an upper part supporting the patch (6) in at least part of the area of the dielectric substrate. System according to claim 5, characterized in that it comprises two different superposed layers, each constituting a dielectric layer (22). 14. The relative dielectric constant of the top dielectric layer (22) is set to the bottom layer (2).
System according to claim 13, characterized in that it is greater than the relative permittivity of 1) and the two layers extend over the entire area of the substrate (2). 15. A conductive insert (23) in which the antenna extends in a portion of the area of the patch (6) between the bottom dielectric layer (21) and the top dielectric layer (22). 14. The system according to claim 13, characterized in that it comprises at least a portion of the region extending below the passageway (32). 16. The body (31) according to claim 7, characterized in that it has a protrusion (34) extending in the plane of the patch (6) in the vicinity of the passage (32). System. 17. Separation slot (1) such that the rear end (15) of the separation slot (17) is at a distance from the two side edges and the front edge.
7) is from the rear edge (10, 11) to the front edge (12) of the patch
The body (31) is connected to the tail (33) by a passageway (32) extending up to and having a constant length and a constant width, the length of the passageway (W2) being in the transverse direction (DT). And the width (L2) of the passage extends in the longitudinal direction (DL) between the front edge (14) and the rear end (15) of the slot (17). ,
The slot separates the rear edge into a body base (10) forming part of the body and comprising the short circuit (S) and a tail base forming part of the tail, The tail base has a width (W4) in the lateral direction (DT), and the tip (13) of the tail consists of a region coupling the tail to the passage and extends in the lateral direction ( W3), the tail has a length (L3) extending in the longitudinal direction (DL) from the tail base to the tip, and the width of the tail is
Transmission system according to claim 7, characterized in that it is defined at each point of the length and extends in the lateral direction (DT). 18. The width (W4) of the base (11) of the tail (33).
Is larger than the width (W2) of the tip (13) of the tail. 19. The width of the tail portion (33) extends from the tip (13) to the base (11) of the tail portion and the width of the tip and the base (
W3, W4) spreads through a plurality of intermediate values.
8. The transmission system according to item 8. 20. The length (L3) of the tail portion (33) is 50% to 100% of the length (L1) of the body (31), and the length relative to the primary frequency (F1). 20. Transmission system according to claim 19, characterized in that the ratio F2 / F1 of the next frequency (F2) is between 1.9 and 2.1. 21. The width (W4) of the base (11) of the tail (33) is
50% to 150% of the width (W1) of the body (31), the passage (32) and the tip (13) of the tail constituting the tail connecting system, the narrower of the connecting system Transmission according to claim 19, characterized in that it constitutes a more effective tail connection width (W3), the effective tail connection width being between 10% and 70% of the width (W4) of the base. system. 22. The edge of the separation slot (17) is defined by the body (31).
Transmission system according to claim 4, characterized in that it is concave on the same side as and convex on the same side as the tail (33). 23. The origin of the separation slot (17) and the short circuit (S) are in the vicinity of a common point of the rear side (10) and the tail side (16), and the separation slot (17). Has a concave surface on the same side as the main body (31) and a convex surface on the same side as the tail portion (33), the two resonance paths extending from the short circuit to the two resonance paths, respectively. 7. One of the two paths extends only into the body (31) and the other path extends into the body and into the tail (33). The transmission system described in. 24. An antenna characterized by the features of the antenna of the system according to any one of claims 1 to 23.